This invention relates to a improved system for cold forming brass shell or cartridge casings. In particular it relates to such a system which provides greater accuracy, faster production, and a simpler and less expensive mechanism. Examples of the prior art may be found in U.S. Class 29, Sub-Classes 1.30, 1.31, 1.32, and Class 72, Sub-Classes 348, 356, and 361. Examples of such prior art are the following U.S. Pat. Nos.: 437,442, 1,363,597, 2,003,438, 3,026,598, 3,408,718, 3,498,221, 3,614,816, 4,198,843.
Since the beginning of metal-cased ammunition, the shape and dimensions of the cartridge case head have been obtained through a cold forming operation called "heading". This cold forming operation typically uses a die in which the casing is placed, an inside punch and an outside punch. Present day heading machines are arranged so that the inside punch feeds the cartridge case into the die, holds the die against the outside punch during the heading operation, ejects the case after the operation is completed, and is then retracted. The outside punch performs the formation of the heading in conjunction with the outside punch but must also be retracted back from the die to allow the ejection of the casing with the newly formed heading.
A typical current machine includes a hopper from which a cartridge case is positioned between the die and an inside punch. A cam-operated slide which holds the inside punch pushes the case into the die and then stops. A locking device protects the cam-operated mechanism against the very substantial heading force provided by the outside punch. A typical small caliber cartridge case needs a heading force of about 20 tons or 200 kilonewtons. A toggle press holds the outside punch and provides the necessary force for the heading operation. The cam-operated slide holding the inside punch then moves further to push the headed case out of the die for ejection. Then the inside punch is retracted. There are several disadvantages to this type of operation. One is that two synchronized mechanisms are required to operate the two punches. Also, the length of the inside punch is so great as to make it too flexible to achieve the required accuracy. In addition, long strokes slow down the production rate. Further, present day heading machines are typically custom designed and use little commercially available sub-assemblies.